• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.75-84
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• 2018

In this research, a bit correction technique of data hiding method in timestamp of MFT entry in NTFS file system is proposed. This method is proposed in two ways, depending on the number of bytes of data to hide. A basic data hiding method using a bit correction technique to solve the problems of the conventional 2-byte technique is proposed. In order to increase the capacity of the data, a 3-byte data hiding method using an extended bit correction technique is proposed. The data hiding method in the timestamps is based on the fact that is not revealed in the Windows explorer window and the command prompt window even if any data is hidden in the timestamp area of less than one second. It is shown that the validity of the proposed method through the experimental two cases of the basic data hiding method by the bit correction method and the 3-byte data hiding method by the extended bit correction method.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.42-50
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• 2001

In this paper, a new technique and theory are proposed which correct the orientation (inclination of a vertical axis) of a cylinder in vertical-micro positioning device. An algorithm for determining the orientation of the cylinder with a pair of displacement sensor units is derived and two types of the correction methods are described. To assess the performance and efficiency of the developed correction technique, the compensation errors originated from the correction algorithm and the machined characteristics of cylinder surface are evaluated from the geometrical considerations and the statistical techniques. Based upon the evaluation results, the maximum compensation error is estimated for the orientation of cylinder and the optimum correction technique is derived.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.5
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• pp.406-415
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• 2010

Purpose: The secondary correction of cleft lip nasal deformity still presents a difficult surgical problems. The present study was aimed to investigate the usefulness of Bardach's technique for secondary correction of cleft lip nasal deformity. Materials and Methods: The subjects were eight patients with unilateral and bilateral cleft lip nasal deformity, who had secondary correction by using Bardach's rhinoplasty technique. Age range was from 2 to 21 years and mean age was 10.6 years. There were 3 boys and 5 girls. Six patients had bilateral and two patients had unilateral cleft lip. Facial photographs were taken before and twenty days after the operation. By using Adobe photoshop, the columella height and the nostril width were measured from the facial frontal photograph and Worm's eye view. The degree of improvement was calculated and statistically analyzed. Results: The degree of improvement of the columella length and the nostril width after Bardach's technique was $70.39{\pm}50.14%$ and $-22.93{\pm}0.15%$ respectively. Bardach's technique resulted in projecting the nasal tip, lengthening the columella, medially advancing the alar bases, restructuring the lower lateral cartilages, and changing orientation of the nostrils from horizontal to oblique. The profile view shows projection of the nasal tip, lengthening of the columella, and the change in the nasolabial angle. The scars remained at the philtrum were matter little in compared with improvement of the nasal appearance. Conclusion: These results indicate that Bardach's technique is an useful surgical technique for secondary correction of cleft lip nasal deformity.

• Journal of the Korea Society of Computer and Information
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• v.23 no.1
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• pp.67-74
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• 2018

In this paper, we propose an efficient scene based non-uniformity correction algorithm which performs the offset correction using the uniform obtained from input scenes for Infrared camera. In general, pixel outputs of a infrared detector can not be uniform. Therefore, the non-uniformity correction procedure need to be performed to make the image outputs uniform. A typical non-uniformity correction method uses a black body at the laboratory to obtain the output of the infrared detector's pixels for two temperatures, HOT and COLD, and calculates the non-uniformity correction parameters. However, output characteristics of the Infrared detector changes while the Infrared camera is operated, the fixed pattern noise of the Infrared detector and dead pixels are generated. To remove the noise, the offset correction is generally performed. The offset correction procedure usually need the additional device such as a thermo-electric cooler, shutter, or non-uniformity correction lens. Therefore, we introduce a general scene based non-uniformity correction technique without additional equipment, and then we propose an improved non-uniformity correction algorithm based on image to solve the problem of the existing technique.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.1
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• pp.99-107
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• 2019

Retinex-based image enhancement is a technique that utilizes the property that the human visual characteristics are sensitive to the difference from the surrounding pixel value rather than the pixel value itself. These Retinex-based algorithms show different characteristics of the improved image depending on the applied color space or gamma correction. In this paper, we set eight different experimental conditions according to the application of color space and gamma correction, and analyze the objective and subjective performance of each Retinex based image enhancement algorithm and apply it to the implementation of Retinex based algorithm. In the case of gamma correction, quantitative low entropy images and low contrast images are obtained. The application of Retinex technique in HSI color space rather than RGB color space is found to be high in overall subjective image quality as well as maintaining color.

• ETRI Journal
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• v.36 no.6
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• pp.894-904
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• 2014

Blind mismatch correction of time-interleaved analog-to-digital converters (TI-ADC) is a challenging task. We present a practical blind calibration technique for low-computation, low-complexity, and high-resolution applications. Its key features are: dramatically reduced computation; simple hardware; guaranteed parameter convergence with an arbitrary number of TI-ADC channels and most real-life input signals, with no bandwidth limitation; multiple Nyquist zone operation; and mixed-domain error correction. The proposed technique is experimentally verified by an M = 4 400 MSPS TI-ADC system. In a single-tone test, the proposed practical blind calibration technique suppressed mismatch spurs by 70 dB to 90 dB below the signal tone across the first two Nyquist zones (10 MHz to 390 MHz). A wideband signal test also confirms the proposed technique.

• Archives of Plastic Surgery
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• v.47 no.6
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• pp.495-504
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• 2020

The primary procedural components of deviated nose correction are as follows: osteotomy to correct bony deviation, septal deviation correction, manipulation of the dorsal septum to correct upper lateral cartilage deviation, and correction of functional problems (manipulation for correction of internal valve collapse and hypertrophy of the inferior turbinate). The correction of tip and nostril asymmetry cannot be overemphasized, because if tip and nostril asymmetry is not corrected, patients are unlikely to provide favorable evaluations from an aesthetic standpoint. Tip asymmetry, deviated columella, and resulting nostril asymmetry are primarily caused by lower lateral cartilage problems, which include deviation of the medial crura, discrepancy in the height of the medial crura, and asymmetry or deformity of the lateral crura. However, caudal and dorsal septal deviation, which is a more important etiology, should also be corrected. A columellar strut graft, correction of any discrepancy in the height of the medial crura, or lateral crural correction is needed to correct lower lateral cartilage deformation depending on the type. In order to correct caudal septal deviation, caudal septal shortening, repositioning, or the cut-and-suture technique are used. Surgery to correct dorsal septal deviation is performed by combining a scoring and splinting graft, a spreader graft, and/or the clocking suture technique. Moreover, when correcting a deviated nose, correction of asymmetry of the alar rim and alar base should not be overlooked to achieve tip and nostril symmetry.

• Korean Journal of Cleft Lip And Palate
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• v.2 no.1_2
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• pp.23-28
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• 1999

The author presents Bardach' s technique for the residual unilateral cleft lip nasal deformity, The key to a successful and stable correction of the nasal deformity is to lengthen the columella on the cleft side and to mobilize alar cartilage from its surrounding tissue, creating a symmetric shape and length, The major advantages of the technique are lengthening of the cleft columella and creation of a symmetric and well-projected nasal tip.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.85-88
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• 1996

New power factor correction(PFC) technique based on the averaged model of boost converter is proposed. Without measurement of input current, power factor correction scheme derived from the averaged model is presented. With the measurements of input voltage and output voltage, the control signal is generated to make the shape of the line current same as the input voltage. The characteristics of input line current distortion is analyzed by considering the generation of duty cycle.

• Journal of the Korean Graphic Arts Communication Society
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• v.15 no.1
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• pp.41-55
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• 1997

We examine various digital halftoning technique and their application to printings. Three such technique are the error diffusion, cluster dither and disperse dither method. This paper describes a new tone correction halftone method to compensate dot gain. Input digital level are transformed by tone correction characteristics. The function of tone correction are solved from the printer response characteristic. The experimental results show that the proposed method is useful and valid.